Food Product Design: Applications - January 2005 - A Sippable Color Spectrum

January 2005

A Sippable Color Spectrum

By Kimberly J. DeckerContributing Editor

Anyone who doubts color's ability to shape consumer preferences would do well to remember the short, sweet life of Crystal Pepsi. Just over 10 years ago, the concept of clarity emerged as a fresh hook, and everything from motor oil to malt liquor was drained of color. Drafting this trend into its "cola wars" battle, PepsiCo Inc., Purchase, NY, test-marketed a colorless version of its signature cola in 1992 and launched it nationally in 1993. Pitched as the "clear alternative," Crystal Pepsi promised traditional cola taste without the traditional color.

Consumers were keen on the novelty at first, but colorless cola toppled a pillar of its own identity: Tradition says cola is supposed to be brown, and without a caramel color cue, our eyes might have prepared our palates for lemon-lime. Cognitive dissonance alone didn't bring about the beverage's demise. "When you add caramel color to cola," explains Dave Tuescher, technical director, Sethness Products Company, Clinton, IA, "you're adding more than just color. Subtle flavor and texture differences occur." With a specific gravity between 1.25 and 1.38, caramel color lends viscous heft, and expert taste panels can single out caramel-free colas solely on mouthfeel.

Cola manufacturers use caramel color to emulsify oil-based flavors, adds Owen Parker, vice president, research & development, D.D. Williamson, Louisville, KY. "So because there was no ability to homogenize the flavors because there was no caramel," he says. "It just didn't taste the same."

In light of the rubies, sapphires and amethysts on beverage shelves today, color-free cola couldn't seem further from the "clear alternative." That beverage's fate remains an object lesson in what can go wrong when product developers tamper with tint without concern for consumer perception and product functionality. In complex beverage systems, answers to color questions are never black and white.

WYSIWYG? Color is the most expressive word in a beverage's visual vocabulary. Without it, that beverage is nearly mute, unable to tell us much about its identity or flavor. Even outward signs of texture, such as carbonation and opacity, only hint at a drink's mouthfeel.

But what you see isn't necessarily what you get. The attempt to decouple flavor from color might have fallen flat in cola, but the lasting popularity of "blue-raspberry" slushies argues that a beverage can tell the eyes one thing and the taste buds another without turning off either. True, orange juice should sometimes be just that: orange juice. But in a marketplace where so many beverages aren't products of nature, psychology and culture have as much say about determining color as Mother Nature.

Still, while beverage designers appreciate creative license as much as the rest, when faced with formulating pumpkin-praline soymilk latte, they long for hints as to its "right" color. After all, asks Stephen Lauro, general manager, colorMaker Inc., Anaheim, CA: "What color is 'strawberry breeze'?"

Staying on message Whatever the answer, it has to be of a piece with an elusive, yet potent, concept: image. Consumers turn to beverages not only to quench thirst, but also to identify with a particular social group or set of values. We are, to paraphrase the maxim, what we drink. Thus, beverage manufacturers have learned that "the visual impressions they make need to be consistent with the packaging, the label and the placement on the shelf or in the vending machines," says Lauro.

Stefan Hake, general manager, GNT USA, Inc., Tarrytown, NY, agrees, describing how message consistency might direct color choice in a nutraceutical tea targeted to mature women. "There you'd have to be extremely careful that the consumer does not feel that you're diverting from nature," he explains. "So in a tea, you might look for a nice, brown color that would almost represent how the consumer would brew the tea at home. Or if it's a fruit tea, you probably would put a little bit of red in there to make it look like a fruit tea or a hibiscus tea. Then the consumer -- in this case, an educated, middle-aged woman -- can differentiate the product as a fruity iced tea."

A youthful energy drink sends a very different message. "If the manufacturer put together a focus group of young athletes playing on the playground," Hake continues, "they'd probably come up with the kind of neon, crazy colors that you see in some of the sports drinks, ranging from a very neon yellow to blue. And that's because those are probably what a thirsty kid coming off the playground is going to pick up and chug."

Some restrictions apply If the message is the medium, coloring that medium with natural or artificial ingredients sends a powerful one. "The market for natural colors is the one that is growing," says Hake. In fact, he credits the beverage industry -- particularly the new-age beverages of the mid-'80s -- for paving the way for natural colors. "It was this 10%-juice industry that realized that there was something they could do to make their drinks look more attractive" to label-reading consumers, he says. "But now you'll find it in mainstream sodas, as well."

However, in FDA's eyes, no such thing as a "natural" color additive exists. What do exist are "certified" colors and colors "exempt from certification." The former includes the seven synthetic colors that, in consumer vernacular, are "artificial." The latter's exemption from certification doesn't mean that they're any less safe or less subject to regulation. Of those approved for human consumption, some are restricted to a very narrow range of applications. However, because FDA doesn't analyze each lot as it does certified colors, the onus rests on manufacturers to ensure compliance with regulations.

A natural advantage Making the swap from certified to exempt hasn't always been easy for beverage manufacturers, who have historically believed that achieving a clean label meant putting up with natural colors' scarcity, expense and instability. As products of nature, exempt colors do vary in supply, price and quality depending upon plant variety and growing conditions. But with demand for natural colors rising, suppliers have streamlined sources and methods, improving quality and consistency.

Manufacturers are also reexamining stereotypes about stability. "Some people are under the impression that synthetics are the more-economical, more-stable choice," says Karen Brimmer, group supervisor, Sensient Technologies Corporation, St. Louis. "However, in some cases, the colors that are exempt from certification exhibit better stability. For example, in a ready-to-drink beverage fortified with vitamin C, carmine is more stable than Red 40, and the stability of beta carotene is enhanced in the presence of ascorbic acid." The FD&C azo dyes Red No. 40, Yellow No. 5 and Yellow No. 6 all contain an N=N double bond vulnerable to attack from metal ions, ascorbic acid and bacterial cultures. No such vulnerability endangers carmine, so by supplementing Red No. 40 with carmine, "if the Red No. 40 starts to fade, you still have the carmine," she says.

First things first Neither naturals nor synthetics display universal stability, particularly when faced with their four archenemies: heat, light, pH extremes and charged compounds. Unfortunately, all four threats, either alone or in combination, are inescapable in beverage systems.

No wonder Byron Madkins, director of food and beverage applications, Chr. Hansen, Milwaukee, considers beverages the most challenging coloring applications. They're not like breakfast cereals, where boxes block damaging ultraviolet (UV) rays, and low water activity inhibits ingredients that promote hue-altering redox reactions. On the contrary, the exposed, watery beverage environment encourages colors, nutrients and beverage solids to mingle. "It's one big soup that has to maintain color stability for the shelf life of the product," he says. "And that's a real challenge."

Before considering pH, heat, light and fortification effects, manufacturers should note the drink's natural color. "If you've got cranberry juice in there, and it's a light red, we know that we're simply enhancing an existing color," says Lauro. But an all-natural drink with a pale, light-brown base, he continues, is "a very different assignment. You're probably going to have to use more color, and you're probably going to have to use a more-sophisticated blend" to forestall fading.

In cloudy beverages, such as grain and dairy milks, yogurt smoothies, and some juice-based drinks, the colorant also has to compete with opacity's obscuring effects. In these, colors will always show up more as pastels than as brilliant gem-tones. A heavier hand with colorants can mitigate some of this effect but, as Lauro says, "it's not going to be bright. It's not going to be sharp. And that can be a challenging visual perception."

Processing matters, too. If there's an aggressive heat process, "then you've just limited yourself in color," Lauro adds. He points out some processors still do it the old-fashioned way: "bringing the beverage up to 190?F, bottling it and shipping it to the warehouse where it remains at 185?F for up to three hours." Such prolonged heat exposure causes browning in some colors -- particularly anthocyanins, grape skin extract and fruit and vegetable juices -- and destroys others. So experts recommend adding colors as late as possible, preferably after pasteurization or even after the beverage has cooled.

While an elegant, clear glass bottle might give a beverage great shelf presence, it also subjects it to fading from fluorescent lighting, especially in drinks with turmeric or Red No. 3. Tinted bottles have traditionally forestalled fading in caramel-colored beers and spirits, but Lauro suggests UV blockers in clear plastic bottles or even overlabels. And it's hard to beat an old-fashioned opaque can -- or a newer Tetra Pak -- for shielding colors from the damaging effects of light.

"What we tell everyone is that natural colors are going to fade," says Lauro. "That's what they do. What you need to do as a food technologist is gauge that fading so that your color outlasts the shelf life of your product." Aside from packaging the beverage wisely, he says, the designer needs to keep an eye on ingredient interactions that accelerate fading, such as those involving ascorbic acid and cations, like calcium.

Madkins agrees, noting that "any kind of charged compound will potentially have some kind of reducing or oxidizing effect on a color molecule." With an FD&C red or yellow, offending ions associate with the color's anionic portion and degrade the part that's responsible for producing the color. Free calcium interacts with annatto, precipitating it or shifting it from orange to pink. Anthocyanins that complex with iron, tin or aluminum fall out of solution or slip toward blue. And iron and magnesium drain carotenoid pigments of color. Other infamous reducing agents include sulfur dioxide, invert sugars and some flavors. Even copper that migrates from plumbing merits attention.

Undissolved or undispersed soy proteins might attract some colors, including Red No. 40. Lauro says that "some of the isolates today are far more soluble than others." Even pulp poses peril, he adds. Carmine has an affinity for proteins on the surface of fruit pulp, so when the two combine they sink to the bottom, giving "brightly colored, red pulp packets," Lauro says, which can create a sort of lava-lamp effect.

The pH factor Beverage pH is another perennial concern for manufacturers. Carmine's strength lies in magenta shades, but below pH 4, carmine appears orange, and above 6 it turns violet. Characteristically orange annatto goes pink below pH 5. Beet extract gives a bluish-red hue around pH 4 and 5, while shifting blue-violet and ultimately yellow-brown farther up the scale. Soy proteins "all tend to have a different isoelectric point," Lauro says, so "they will fall out of solution at different pH levels, and that pH will greatly affect the appearance of an anthocyanin, which is a true navy blue at pH 7, flaming red at pH 3 and everything in between."

Even caramel -- stable along the scale from 2 to 10 -- isn't immune to pH. Caramel colors carry a positive or negative charge depending on their manufacture and their color class. Beverages are charged because of tannins, plant material, proteins or other ingredients. A soft drink is usually negative, whereas beers are mostly positive. The developer has to match the beverage charge with that of the caramel to prevent positive and negative elements from combining and falling out of solution. "Say you have negative ions in a natural juice that has some tannic acid, which is negative," says Tuescher. "You put a positive caramel color in there, and the positive and negative attract and precipitate."

However, caramel color's charge also depends on whether the beverage pH is above or below the color's isoelectric point -- above it, the caramel is negative; below it, positive. Formulating a negatively charged, pH 3 soft drink requires a negative caramel that, in order to be negative, is above its isoelectric point at pH 3. So, a caramel with an isoelectric point below pH 3 will work -- likely from the class IV "soft-drink caramels," which range from pH 0.5 to 2.0.

Using acid-stabilized colors permits more leeway in matching colorant to pH. Acid-proof annatto, in addition to being emulsified for water-solubility, won't precipitate between pH 2 and 7 or turn pink below pH 5. This suits it to citrus drinks, tropical punch and soy- or milk-based beverages, at usage levels from 0.01% to 0.20%. Acid proofing in pH-stable caramel lets the color remain stable for months in beverage concentrates with robust phosphoric-acid concentrations.

Adding value Madkins has found that blending a specific range of anthocyanin pigment profiles can initiate inter- and intramolecular bonding and co-pigmentation effects to stabilize the colors. "So in one application, you may have red cabbage with a certain heat or light stability. But if I take red cabbage and co-blend that with one or two other anthocyanins from a grape skin extract and then put them in the same application, we're finding that the stability may increase by 10% or 30% in different beverage applications," he says. He's also enhanced the heat stability of carmine and cochineal by co-processing them with sugar blends, which allows the color to be much more stable through beverage-pasteurization steps.

Microencapsulating insoluble pigments in a sugar-starch medium safeguards pigments while rendering them water-dispersible. "It's not an emulsification," Madkins explains, "but rather taking a pigment that is completely insoluble and putting it into a matrix that, first, protects it in that application, and then makes it water-dispersible." This increases stability and provides a clouding effect because it's dispersed, not dissolved. The pigments will eventually settle out of solution, so he suggests using them in applications with solids, like a pulp base or a high juice content, or soy- and milk-based beverages.

Because FD&C lakes -- insoluble pigments made by precipitating a dye onto an aluminum-hydroxide substrate -- color by dispersion, they too tend to settle in beverages. However, lakes color powder in a dry mix more effectively than FD&C dyes, which are generally only visible in the reconstituted drink. Because lakes turn colorless below pH 4, manufacturers can have fun with kids by using a Yellow No. 6 lake to color the low-pH drink powder orange, and Blue No. 1 dye to color the dissolved beverage. As the drink's acidity breaks down the lake, what started out orange in the packet turns blue in the glass. Manufacturers of meal-replacement beverages can take advantage of lakes' retort stability by homogenizing them into applications where retort-labile dye wouldn't survive. These lakes will remain suspended in most cases, but it never hurts to label the can "shake well before serving."

Thinking outside the crayon box Beverage manufacturers once assumed that only FD&C lakes and dyes could provide a vivid, varied palette. As more and better natural colorants come on line, however, that presumption is fast fading. "Maybe 7 to 10 years ago," Madkins says, "the idea was that if I wanted something bright and vibrant to grab the consumer's eye, then it had to be a synthetic." But only Red No. 40, Yellow No. 5, Yellow No. 6, Blue No. 1 and occasionally Green No. 3 are practical in most beverages. Naturals add more crayons to the box.

Caramel color, associated mainly with cola, enhances yellows in lemonade and eggnog, dampens beet extract's glaring-red tones in a cherry-flavored drink, and guarantees that root beers are rich and reddish-black.

However, naturals come up short in greens and blues -- due less to nature's lack of imagination than to bureaucratic red tape. FDA grants little opportunity to color beverages green or blue without synthetics. Using permissible naturals alone, "the bluest shades are typically found with certain anthocyanins, such as red cabbage, which would give a red shade with blue notes," explains Susan Brunjes, natural colors chemist, Sensient. "Blue shades can be achieved at a higher pH -- 5.5 and above -- with anthocyanins, but this would apply to a very limited number of applications that fall into this pH range, and stability could be compromised."

While sodium copper chlorophyllin lends a natural green to citrus-based dry beverage mixes, at this point, that's the only beverage it can color. Hope of expanding its use is "probably approximately two years away," says Brunjes.

Color technologists have developed a handful of certified/exempt blends that generate blues and greens. Brunjes mentions that a tag-team of red cabbage juice and Blue No. 1 offers "bright-purple shades in applications where technically appropriate. Other options would be to combine Blue No. 1 with carmine or cochineal extract." Mixing carmine and yellowish caramel color yields a respectable green.

Because turmeric produces a brighter shade of yellow than Yellow No. 5, Madkins adds that "if you want to get some of the almost-neon-green effects that are popular in beverage applications, turmeric and Blue No.1 make a really neat combination."

Natural blends have also brought beverage colors back to nature's own hues. A classic example, says Lauro, is "tomato red." A tomato drink might get a realistic tone with lycopene extracted from the tomato. But with the petition for lycopene extract's exempt status still pending -- and given its short shelf life and heat instability -- "we make tomato red by blending carmine, oleoresin of paprika and a touch of caramel color," he says, emulsifying the oleoresin with mono- and diglycerides or, in a natural-leaning drink formulation, lecithins and gums.

"We like to think that you can achieve almost any hue with natural color blends," says Lauro. That's why going from the snack aisle to the beverage section often feels like stepping into a jeweler's shop. "It's absolutely beautiful," he continues. "It's very much like a jewelry store, and the jewelry that gets chosen is the one that stands out visually. Perhaps nowhere do convenience, nutrition and color combine better than in beverages."

Kimberly J. Decker, a California-based technical writer, has a B.S. in Consumer Food Science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay area, where she enjoys eating and writing about food. You can reach her at [email protected] .

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